We plan to study 12 patients greater than 18 or equal to 18 years old with moderate to severe plaque-type psoriasis ( with more than or equal to 15 pasi score). The patients will be randomized to one of the three dose groups or placebo. Patients will have to discontinue their anti-psoriasis medications 4 weeks prior to enrolling in the study.Skin biopsies of the psoriatic lesions will performed at baseline and after completion of the study.